1. Field of the Invention
This invention relates generally to devices and systems for mixing natural gas or any gaseous fuel with air in the correct proportions for combustion in a gas engine, and is particularly concerned with a fuel control system and method for controlling a natural gas engine for the purpose of reducing exhaust emissions and improving engine performance.
2. Related Art
The main concern that engineers had when designing the older engines and their fuel systems was engine performance and durability without any regard for exhaust emissions. Over the years numerous systems for controlling emissions have evolved utilizing a catalytic converter, an exhaust gas sensor, and a fuel modulating system to control the mixture for reduced emissions.
Some of the prior art devices that have been used rely on various types of supplemental fuel metering, biasing on pneumatic pressure regulator, or limited throttling of the main fuel supply. They have required substantial amounts of external support equipment and electrical interconnections. They have suffered from slow response and generally have not been particularly easy, convenient or economical to install, operate or use. Few have had any significant degree of self-containment or full fuel authority.